Full to brimming

Every minute, another 157 humans arrive on the planet. Four of them are born in developed nations; the rest are born into a world of want and need—51 of them in India alone. That’s helped to increase the global population more than 130 per cent since 1960. The planet is expected to sustain around 1.6 million extra people every week.

The population graph doesn’t so much resemble a hockey stick as a builder’s square: 10,000 years ago, there were around a million people. It took until 1800 for the global popu­lation to reach its first billion, due to setbacks such as the Great Famine and the Black Death (after which, in 1350, there were just 370 million people on Earth), but it took only another 130 years to hit two billion. Growth rates peaked in the early ‘60s at 2.2 per cent, the height of the baby boom, but have flattened since, holding steady at around one per cent. That lull coaxed a scientific consensus that the world’s population would level off somewhere around 2050 at nine billion people, after which it would begin to decline—a mantra, repeated for two decades, that soothed policymakers and knocked over­population off the front page.

But now it’s back. In September, researchers at the University of Washington and the United Nations re-analysed recent population data, applying new, more perceptive probabilistic tools that debunked our old thinking, and delivered a sobering revision:

“There is an 80 per cent probability that the world population, now 7.2 billion, will increase to between 9.6 and 12.3 billion in 2100,” announced Adrian Raftery, University of Washington professor of statistics and sociology.”

Those numbers may sound vague, but they’re stringent compared with previous efforts, and when they’re fed into scenarios around climate change, food production, resource scarcity and global security, they add a discomforting frisson to the future.

The Earth is already in overdraft. Environmental non-profit organisation Footprint Network calculates the point each year at which we use up the planet’s annual renewable production. “Earth Overshoot Day” marks our annual slide into ‘ecological debt’, exhausting the resources produced­ timber, fish, nutrients—and saturating the natural systems that absorb our waste, such as carbon dioxide. In 2000, Overshoot Day arrived in early October. This year, we went into the red on August 19. It comes around earlier every year.

New probabilistic tools have stripped away the uncertainty around previous population estimates, tightening the range around the United Nations’ medium growth projection. The Gerland study set the UN’s low variant for 2100 at 6.7 billion (world population is already 7.3 billion); its high variant is 16.6 billion. However, forecasting country-by-country fertility rates 85 years hence is a difficult exercise—few forecasters in 1980 would have predicted birth rates in Bangladesh and Iran to plummet from around six per woman to two, as they now stand.

In 1960, most countries nurtured more resources than they consumed: humans left around a quarter of the Earth’s renewable productivity untouched. By 2008, according to WWF, we were drawing 1.5 times those resources annually. Today, just 14 per cent of the world’s people are living within nature’s means. Footprint reckons that by 2050, under current rates of consumption, it will need three Earths to keep society provisioned.

That’s despite the fact that, among developed nations (and a few of the devel­oping ones), global fertility rates have been falling for some time. In 1950, women had an average of 4.92 children; today, they have 2.56. Some of that has been achieved by policy, but a lot is down to contraception, or the empowerment of women, or both.

Wherever women’s status, autonomy, employment oppor­tunities and access to birth control rise, birth rates fall. The evidence is ample, but cultural, political and economic forces still bar the way for far too many: the UN estimates that more than 220 million women in the developing world either want no more children or want to determine the timing of their next, yet they cannot. In countries such as Nigeria, Uganda, the Democratic Republic of the Congo and Afghanistan, women still bear more than five children in their lifetimes.

Falling fertility alone, then, will not stem the human tide. Nor will pandemics, a globally enforced one-child policy or a Third World War, according to University of Adelaide researchers. In September, Corey Bradshaw and Barry Brook released a paper which found that the “inexorable demographic momentum” of the global human popula­tion is practically unstoppable. “There are no easy policy levers to change the size of the human population substantially over coming decades,” they wrote.

“We’ve gone past the point where we can do it easily,” said Bradshaw. “We just can’t stop it fast enough… Even draconian measures for fertility control still won’t arrest that growth rate—we’re talking century-scale reductions rather than decadal scale.”

Better, the pair conclude, to prioritise reducing our rampant consumption. On the face of it, overpopulation and consump­tion would seem to represent some kind of parlous feedback loop, but it’s a mistake to conflate them: they are separated, meta­phorically and demographically, by the have/ have-not divide. Population growth is, nomi­nally at least, happening in the developing world, while overconsumption is the predilec­tion of the wealthy West (and the aspiring East). Climate change data supports this: the most rapid population growth is happening in developing nations with negligible emissions profiles. The fact is that the world’s poor are not stuffing up the atmosphere; nor are they exhausting planetary resources—we are.

Yes, but surely not New Zealand? With just 4.5 million souls, 16 to the square kilometre, New Zealand has fertility rates that have fallen steadily over the past three decades to 2.05 births per woman in 2012. By 2061, we can still expect a sum total of only six million. But when measuring consumption, researchers use the Global Hectare—a measure of the productive land available worldwide to meet our demands. By one calculation, there are some 11.9 billion global hectares out there. It’s a simple matter to then derive the ‘fair Earth share’ of ecological goods and services available to each of us. When I was born— 1960—I had 3.96 global hectares to sustain me. I now have 1.7—that’s my environmental budget.

Ecological footprint is the measure of the biological production available nationally versus resources consumed. While New Zealand’s position has improved since 2008, we nevertheless consume nearly twice our fair share—the world’s sustainable average biocapacity per person is 1.7 global hectares, and New Zealanders on average use more than three hectares.

But like all New Zealanders, I live in perpetual overdraft. By one estimate, we actually occupy nearly five hectares each—five times more than a person in rural India. If everyone on Earth lived like a New Zealander, analysis has shown, they would need 2.1 planets to sustain them.

In 2007, market research called the 8 Tribes project identified the nation’s broad consumer groups by demographic, income and philosophy. It put to rest the myth of the ‘typical Kiwi’ and revealed instead a nation of diverse, very disparate communi­ties. In 2009, those tribes formed the basis of The New Zealand Footprint Project, a three-year analysis of New Zealanders’ ecological impact.

Hardest on the environment was the North Shore tribe: a demographic charac­terised by “preferences for high levels of consumption, travel, and large houses”. They commanded 3.7 fair Earth shares each. Even the Raglan tribe, a community synonymous with self-sufficiency, simpler consumption and lower incomes, still used 1.7 shares.

In Wellington, the average environmental footprint has gone up 45 per cent in the past five decades. New Zealand only seems benign: in reality, we drive almost everywhere, ship goods the length of the country (food and beverage make up a full 56 per cent of our national footprint), import and buy a lot of stuff (consumer goods make up another 23 per cent) and often fly vast distances. Our reliance on agriculture means our greenhouse gas emissions are sky high and set to climb another 50 per cent. Per capita, New Zealanders are the fifth-worst climate polluters in the world.

Population is a pressing environmental issue, but it’s the rich nations’ obsession with consumption that will push the biosphere to the wall.